Here is how much heat affects performance in the RX8
06-23-2004, 09:05 PM
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Originally posted by BLUE PHI RX-8
Did anyone other than me notice that the dates on the time slips showed June 23, 2004. Their date stamp must be off by one day. Maybe the effect of the 2004 leap year.
Did anyone other than me notice that the dates on the time slips showed June 23, 2004. Their date stamp must be off by one day. Maybe the effect of the 2004 leap year.
06-23-2004, 09:16 PM
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Originally posted by syntrix
Sometimes the equipment is working exceptional for the times, but the date and time seem to be off on a LOT of tracks timeslips. guess they just don't care about that stuff.
Sometimes the equipment is working exceptional for the times, but the date and time seem to be off on a LOT of tracks timeslips. guess they just don't care about that stuff.
06-23-2004, 09:37 PM
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Originally posted by Zeltar
Say what? Hotter air does not mean less dense air. First, let's say it did for a minute. In that case, you would be burning too rich (more fuel for the amount of air you take in). That's why in the carburetor days of the side draft Weber’s, we had jet kits to change to smaller sizes when we went up the mountains.
Okay now - quite often, when the air gets hot, it's an indication that the barometer (i.e. the amount of weight the air weighs which is indicative of how much air is above you) is higher. This then, means denser air, not “less dense” air.
Most of us know that if you are at sea level, or hey even better, below sea level like in Death Valley, that your car is going to run faster than it will at 10,000 Feet. The average atmospheric pressure at sea level is 29.92. Velocity’s best run with the CZ1 was at 30.83 (which is below sea level).
I suspect one of two things. Either the CZ1 modification slowed the car down (not likely, according to what I read on this board), or it is the humidity! At 100%, were you under water or something? Around my house in California, when it’s 87% humidity, there is a steady mist and the ground is wet. That said, I wonder if your tires had enough grip for a drag speed test.
Say what? Hotter air does not mean less dense air. First, let's say it did for a minute. In that case, you would be burning too rich (more fuel for the amount of air you take in). That's why in the carburetor days of the side draft Weber’s, we had jet kits to change to smaller sizes when we went up the mountains.
Okay now - quite often, when the air gets hot, it's an indication that the barometer (i.e. the amount of weight the air weighs which is indicative of how much air is above you) is higher. This then, means denser air, not “less dense” air.
Most of us know that if you are at sea level, or hey even better, below sea level like in Death Valley, that your car is going to run faster than it will at 10,000 Feet. The average atmospheric pressure at sea level is 29.92. Velocity’s best run with the CZ1 was at 30.83 (which is below sea level).
I suspect one of two things. Either the CZ1 modification slowed the car down (not likely, according to what I read on this board), or it is the humidity! At 100%, were you under water or something? Around my house in California, when it’s 87% humidity, there is a steady mist and the ground is wet. That said, I wonder if your tires had enough grip for a drag speed test.
06-24-2004, 08:09 AM
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Originally posted by Zeltar
Say what? Hotter air does not mean less dense air. First, let's say it did for a minute. In that case, you would be burning too rich (more fuel for the amount of air you take in). That's why in the carburetor days of the side draft Weber’s, we had jet kits to change to smaller sizes when we went up the mountains.
Okay now - quite often, when the air gets hot, it's an indication that the barometer (i.e. the amount of weight the air weighs which is indicative of how much air is above you) is higher. This then, means denser air, not “less dense” air.
Say what? Hotter air does not mean less dense air. First, let's say it did for a minute. In that case, you would be burning too rich (more fuel for the amount of air you take in). That's why in the carburetor days of the side draft Weber’s, we had jet kits to change to smaller sizes when we went up the mountains.
Okay now - quite often, when the air gets hot, it's an indication that the barometer (i.e. the amount of weight the air weighs which is indicative of how much air is above you) is higher. This then, means denser air, not “less dense” air.
06-24-2004, 11:48 AM
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Hot air is definately less dense air.
Ever heard of a hot air baloon? It rises because the hot air is less dense.
You are correct that air at elevation is also less dense.
So, 70 degree air at Sea Level is mode dense than 70 deg air at 5000 ft. So the best is to run at cool temps at sea level (or below if you are in New Orleans ).
Ever heard of a hot air baloon? It rises because the hot air is less dense.
You are correct that air at elevation is also less dense.
So, 70 degree air at Sea Level is mode dense than 70 deg air at 5000 ft. So the best is to run at cool temps at sea level (or below if you are in New Orleans ).
06-24-2004, 06:56 PM
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Originally posted by Reeko
Hot air is definately less dense air.
Ever heard of a hot air baloon? It rises because the hot air is less dense.
You are correct that air at elevation is also less dense.
So, 70 degree air at Sea Level is mode dense than 70 deg air at 5000 ft. So the best is to run at cool temps at sea level (or below if you are in New Orleans ).
Hot air is definately less dense air.
Ever heard of a hot air baloon? It rises because the hot air is less dense.
You are correct that air at elevation is also less dense.
So, 70 degree air at Sea Level is mode dense than 70 deg air at 5000 ft. So the best is to run at cool temps at sea level (or below if you are in New Orleans ).
06-24-2004, 10:14 PM
#32
Originally posted by smrx8
THOSE TIMES JUST GIVE ME DEPRESSION!!! a neon low 14 that some crap
THOSE TIMES JUST GIVE ME DEPRESSION!!! a neon low 14 that some crap
06-24-2004, 10:34 PM
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Originally posted by red_rx8_red_int
Yea, me too! I never knew about this car. Need to make sure I don't challange one until I get some mods going. But damn its going to take a lot to get sub 6 times. OK, I'm more calm now. They advertise 240 HP, supposedly we have 238 HP, but they are a full second faster. What gives? I can't believe its that much lighter.
Yea, me too! I never knew about this car. Need to make sure I don't challange one until I get some mods going. But damn its going to take a lot to get sub 6 times. OK, I'm more calm now. They advertise 240 HP, supposedly we have 238 HP, but they are a full second faster. What gives? I can't believe its that much lighter.
06-25-2004, 02:03 AM
#34
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As we all now know, the harder and hotter the car is run the less efficient the performance is. One dead give away that the Renisis runs super hot is when the car is turned off after a hard run or a +100 deg day and those fans kick in and run for about 10 min or so. Durring road racing here in the Valley of the Sun the season goes on break durring the summer months for obvious reasons, but the rest of the year is open for bussiness. One thing we've learned even at 50-60 deg temps, after about 20 laps the car starts to suffer a power loss due to rising engine temps. On a road course its more noticable accelerating out of a turn, mashing the gas trying to get all the tourqu possible. The reason is because the heavy braking just before the turn raises the temps of the brakes emensly but also because the drop in MPH decreases the air flow through the radiator and engine bay.
Adding a larger vented or functional front bumper will help out bigtime. Also I scored a PWR racing radiator that will soon be available and I have had better results with it installed. The engine temps have dropped a bit when running hard and I dont fret any more starting it up on 109 deg days.
I think the last thing I'll do to the cooling system will be some silicon rad hoses, Samco should have them available soon.
Lastly I've been thinking of a DIY radiator spray like the intercooler versions commonly seen. Mainly just for the track, every little bit helps ya know.
Adding a larger vented or functional front bumper will help out bigtime. Also I scored a PWR racing radiator that will soon be available and I have had better results with it installed. The engine temps have dropped a bit when running hard and I dont fret any more starting it up on 109 deg days.
I think the last thing I'll do to the cooling system will be some silicon rad hoses, Samco should have them available soon.
Lastly I've been thinking of a DIY radiator spray like the intercooler versions commonly seen. Mainly just for the track, every little bit helps ya know.
06-25-2004, 03:52 AM
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Originally posted by red_rx8_red_int
Yea, me too! I never knew about this car. Need to make sure I don't challange one until I get some mods going. But damn its going to take a lot to get sub 6 times. OK, I'm more calm now. They advertise 240 HP, supposedly we have 238 HP, but they are a full second faster. What gives? I can't believe its that much lighter.
Yea, me too! I never knew about this car. Need to make sure I don't challange one until I get some mods going. But damn its going to take a lot to get sub 6 times. OK, I'm more calm now. They advertise 240 HP, supposedly we have 238 HP, but they are a full second faster. What gives? I can't believe its that much lighter.
06-25-2004, 10:09 AM
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That is terrible. WhenI paid that much for a car I didn't expect to have the "horsepower sales trick" pulled on me. I would rather be told "The RX-8 puts out 185 hp to the wheels" than "This car has 238 hp!". If I was to compare these two cars I would see that the RX-8 has 8 more horsepower than the neon. I guess this is just the world of sales and I shouldn't be too hard on Mazda. I am just dissappointed as everyone else to see actual horsepower ratings from this car. Don't get me wrong, I love my car... but what is the actual horsepower and what does Mazda have to say about it's 238 HP?
06-25-2004, 10:46 AM
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Originally posted by ByeByeHonda
That is terrible. WhenI paid that much for a car I didn't expect to have the "horsepower sales trick" pulled on me. I would rather be told "The RX-8 puts out 185 hp to the wheels" than "This car has 238 hp!". If I was to compare these two cars I would see that the RX-8 has 8 more horsepower than the neon. I guess this is just the world of sales and I shouldn't be too hard on Mazda. I am just dissappointed as everyone else to see actual horsepower ratings from this car. Don't get me wrong, I love my car... but what is the actual horsepower and what does Mazda have to say about it's 238 HP?
That is terrible. WhenI paid that much for a car I didn't expect to have the "horsepower sales trick" pulled on me. I would rather be told "The RX-8 puts out 185 hp to the wheels" than "This car has 238 hp!". If I was to compare these two cars I would see that the RX-8 has 8 more horsepower than the neon. I guess this is just the world of sales and I shouldn't be too hard on Mazda. I am just dissappointed as everyone else to see actual horsepower ratings from this car. Don't get me wrong, I love my car... but what is the actual horsepower and what does Mazda have to say about it's 238 HP?
06-25-2004, 11:58 AM
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Originally posted by Zeltar
Yes, if you heat air, you can make it less dense thus causing the pocket to rise against cooler air. Once risen, it still remains that the weight of the air above you is the barametric pressure. It is the final and actual true measurement of the density of air. That's why turbo chargers are effective. Notice, we don't put the air through the air conditioner before injecting it!
Yes, if you heat air, you can make it less dense thus causing the pocket to rise against cooler air. Once risen, it still remains that the weight of the air above you is the barametric pressure. It is the final and actual true measurement of the density of air. That's why turbo chargers are effective. Notice, we don't put the air through the air conditioner before injecting it!
What do you think an intercooler does?
Also, it's not that you *can* make it less dense, it's that you DO actually make it less dense when you heat it. There's no way around that, all else being equal. Hotter air IS less dense than cooler air.
A hot day has LESS barometric pressure than a cold day. Just like a high altitude place has less barometric pressure than a low altitude place. So, if the day is hotter today than 6 months ago, the air is less dense than 6 months ago.
Turbochargers are effective because they compress air and you get more air/fuel into the combustion chamber than you otherwise could, thus making more power. They don't depend on the outside barometric pressure. Actually, the only thing that barometric pressure has to do with a turbo is that the boost gauge and the boost controller are usually based on "gauge" values instead of absolute values, which means that they are referenced to the barometric pressure and not to absolute pressure. They can compress the air X amount of times, independently of if you are at high altitude or low altitude or if it's cold or hot.
Compressing the air with a turbo also heats the air and that is why you do put the air through an intercooler before injecting it. Cooling that heated air makes it denser also.
06-25-2004, 01:04 PM
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Originally posted by Vrimmick
There is no horsepower sales trick!!! RX-8 cannot be dyno-ed that easily, but surely claimed 238hp are under the hood. Neon gains that half second from 0-60 only because it gets to the power peak sooner, thanks to a higher torque but then it is not much better. So stop listening to these lamenting guys... After all you wouldn't want to drive neon would you? And dont worry about what you paid and the relevant performance you're getting. New bmw 530 that runs north of 50k is much slower than rx8, not to mention neon.
There is no horsepower sales trick!!! RX-8 cannot be dyno-ed that easily, but surely claimed 238hp are under the hood. Neon gains that half second from 0-60 only because it gets to the power peak sooner, thanks to a higher torque but then it is not much better. So stop listening to these lamenting guys... After all you wouldn't want to drive neon would you? And dont worry about what you paid and the relevant performance you're getting. New bmw 530 that runs north of 50k is much slower than rx8, not to mention neon.
06-25-2004, 01:12 PM
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Originally posted by brillo
so how do you counter act this? better radiator? CAI? the intakes don' seem to do much for the car. what other ways can you cool the engine down?
so how do you counter act this? better radiator? CAI? the intakes don' seem to do much for the car. what other ways can you cool the engine down?
06-25-2004, 01:21 PM
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Originally posted by IkeWRX
This an RX-8 can't be dynoed stuff is BS, it certainly can and has been many time. The dyno results correspond very well to the times and traps it gets at the track. Also from a roll it just gets worse for the RX-8 compared to an RX-8 considering the MY04 SRT-4 traps up to 103mph which is about on par with an EVO, STi, and faster than a 350Z and considerably faster than an RX-8. 8-12 MPH higher trap speeds is a HUGE difference.
This an RX-8 can't be dynoed stuff is BS, it certainly can and has been many time. The dyno results correspond very well to the times and traps it gets at the track. Also from a roll it just gets worse for the RX-8 compared to an RX-8 considering the MY04 SRT-4 traps up to 103mph which is about on par with an EVO, STi, and faster than a 350Z and considerably faster than an RX-8. 8-12 MPH higher trap speeds is a HUGE difference.
neon srt-4: 0-60 5.6sec, 1/4 mile 14.2sec at 102mph
rx8: 0-60 5.9, 14/mile 14.5 at 96mph
and remember neon is 200 pound lighter and has much higher torque number
Last edited by Vrimmick; 06-25-2004 at 01:33 PM.
06-25-2004, 01:35 PM
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Originally posted by Vrimmick
It has been dynoed many times but improperly. This is not 70's or 80's anymore. Modern BMW and RX8 cannot be measured on a dyno without the airflow. For example Dinan 470hp M5 produces only 334 at the wheels, when measured on a dyno. Put 75mph airflow on the radiator and dyno shows 411. And you can shove your trap speed analysis... Seems that by negating rx8's true potential you are trying to justify wrong car purchase decision...
It has been dynoed many times but improperly. This is not 70's or 80's anymore. Modern BMW and RX8 cannot be measured on a dyno without the airflow. For example Dinan 470hp M5 produces only 334 at the wheels, when measured on a dyno. Put 75mph airflow on the radiator and dyno shows 411. And you can shove your trap speed analysis... Seems that by negating rx8's true potential you are trying to justify wrong car purchase decision...
How am I negating the RX-8s true potential, I'm just stating facts. The SRT-4 is faster than the RX-8 in every gear at any speed, it's not my problem you have a hard time dealing with that.
If you were so of your purchase and the potential of the RX-8 you wouldn't even be argueing this with me, you would just accept that the SRT-4 and many other cars are faster and be happy with your RX-8.
06-25-2004, 01:39 PM
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Originally posted by Vrimmick
neon srt-4: 0-60 5.6sec, 1/4 mile 14.2sec at 102mph
rx8: 0-60 5.9, 14/mile 14.5 at 96mph
and remember neon is 200 pound lighter and has much higher torque number
neon srt-4: 0-60 5.6sec, 1/4 mile 14.2sec at 102mph
rx8: 0-60 5.9, 14/mile 14.5 at 96mph
and remember neon is 200 pound lighter and has much higher torque number
06-25-2004, 01:46 PM
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Originally posted by IkeWRX
This an RX-8 can't be dynoed stuff is BS, it certainly can and has been many time. The dyno results correspond very well to the times and traps it gets at the track. Also from a roll it just gets worse for the RX-8 compared to an RX-8 considering the MY04 SRT-4 traps up to 103mph which is about on par with an EVO, STi, and faster than a 350Z and considerably faster than an RX-8. 8-12 MPH higher trap speeds is a HUGE difference.
This an RX-8 can't be dynoed stuff is BS, it certainly can and has been many time. The dyno results correspond very well to the times and traps it gets at the track. Also from a roll it just gets worse for the RX-8 compared to an RX-8 considering the MY04 SRT-4 traps up to 103mph which is about on par with an EVO, STi, and faster than a 350Z and considerably faster than an RX-8. 8-12 MPH higher trap speeds is a HUGE difference.
06-25-2004, 01:49 PM
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what do you think about this>? https://www.rx8club.com/showthread.p...light=cryogenic
Originally posted by O.R.A.
What do you think an intercooler does?
Also, it's not that you *can* make it less dense, it's that you DO actually make it less dense when you heat it. There's no way around that, all else being equal. Hotter air IS less dense than cooler air.
A hot day has LESS barometric pressure than a cold day. Just like a high altitude place has less barometric pressure than a low altitude place. So, if the day is hotter today than 6 months ago, the air is less dense than 6 months ago.
Turbochargers are effective because they compress air and you get more air/fuel into the combustion chamber than you otherwise could, thus making more power. They don't depend on the outside barometric pressure. Actually, the only thing that barometric pressure has to do with a turbo is that the boost gauge and the boost controller are usually based on "gauge" values instead of absolute values, which means that they are referenced to the barometric pressure and not to absolute pressure. They can compress the air X amount of times, independently of if you are at high altitude or low altitude or if it's cold or hot.
Compressing the air with a turbo also heats the air and that is why you do put the air through an intercooler before injecting it. Cooling that heated air makes it denser also.
What do you think an intercooler does?
Also, it's not that you *can* make it less dense, it's that you DO actually make it less dense when you heat it. There's no way around that, all else being equal. Hotter air IS less dense than cooler air.
A hot day has LESS barometric pressure than a cold day. Just like a high altitude place has less barometric pressure than a low altitude place. So, if the day is hotter today than 6 months ago, the air is less dense than 6 months ago.
Turbochargers are effective because they compress air and you get more air/fuel into the combustion chamber than you otherwise could, thus making more power. They don't depend on the outside barometric pressure. Actually, the only thing that barometric pressure has to do with a turbo is that the boost gauge and the boost controller are usually based on "gauge" values instead of absolute values, which means that they are referenced to the barometric pressure and not to absolute pressure. They can compress the air X amount of times, independently of if you are at high altitude or low altitude or if it's cold or hot.
Compressing the air with a turbo also heats the air and that is why you do put the air through an intercooler before injecting it. Cooling that heated air makes it denser also.
06-25-2004, 02:10 PM
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Originally posted by Seenitall
Yup folks accept the 8 for what it is-dont worry about the other guy.
Yup folks accept the 8 for what it is-dont worry about the other guy.
Remember, no matter how fast it is it's still a Neon when it's parked. :D
06-25-2004, 02:17 PM
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Originally posted by IkeWRX
The SRT-4 is faster than the RX-8 in every gear at any speed, it's not my problem you have a hard time dealing with that.
If you were so of your purchase and the potential of the RX-8 you wouldn't even be argueing this with me, you would just accept that the SRT-4 and many other cars are faster and be happy with your RX-8.
The SRT-4 is faster than the RX-8 in every gear at any speed, it's not my problem you have a hard time dealing with that.
If you were so of your purchase and the potential of the RX-8 you wouldn't even be argueing this with me, you would just accept that the SRT-4 and many other cars are faster and be happy with your RX-8.
Last edited by Vrimmick; 06-25-2004 at 02:20 PM.
06-25-2004, 07:03 PM
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Originally posted by Vrimmick
blah, blah, blah SRT-4 is a faster car and the numbers I showed prove that, so I dont have a hard time dealing with that. And rx8 has 238hp ha ha ha ha, and the trap times... ahhh some lazy drivers man... Let me enjoy these 238 ponies man and stop shuffling trap times please...
blah, blah, blah SRT-4 is a faster car and the numbers I showed prove that, so I dont have a hard time dealing with that. And rx8 has 238hp ha ha ha ha, and the trap times... ahhh some lazy drivers man... Let me enjoy these 238 ponies man and stop shuffling trap times please...